Solvent vapor fiberset process for durable press finishing of cellulosic fabrics

ABSTRACT

Durable press properties are imparted to cellulosic textiles by utilization of this &#39;&#39;&#39;&#39;FIBERSET&#39;&#39;&#39;&#39; process. Polymer fixation is carried out in the vapors of a boiling organic solvent. Single and two-step variations of the process can be employed to fit the specific end goals. The finished goods have good strength, abrasion resistance, and durable-press properties.

United States Patent Cashen et a1.

I45] Aug. 26, 1975 l SOLVENT VAPOR FIBERSET PROCESS FOR DURABLE PRESS FINISHING ()F CELLULOSIC FABRICS [75] Inventors: Norton A. Cashen, Metuirie; Robert M. Reinhardt; John D. Reid. both of New Orleans. all of La.

1731 Assignee: The United States of America as represented by the Secretary of Agriculture, Washington. DC,

(221 Filed: June 20, I973 1211 Appl. No; 37I,642

[51] Int. Cl) D06M 15/12 [58I Field of Search ll7/l39.4; 8/183 [56] References Cited UNITED STATES PATENTS 3.374.107 3/1968 Cotton S/HU X 3.472.606 10/1969 Gctchcll et al. 8/183 X 1546.006 12/1970 Verburg et al..... 8/183 X 3.617.195 11/1971 Moysc 8/183 X 3.709.657 1/1973 Hollies et a1 8/1 l5.7 X 3.784.355 1/1974 Fielding 8/186 X Primary ExaminerCameron K. Weiffenbach Ass/Mun! Examiner-Ralph E. Varndell. Jr. A!mrney,Agen1. or Firm-M. Howard Silvcrstein; Max D. Hensley [57] ABSTRACT 6 Claims, N0 Drawings SOLVENT VAPOR FIBERSET PROCESS FOR DURABLE PRESS FINISHING OF CELLULOSIC FABRICS This invention relates to a solvent vapor polymerdeposition process for durable press finishing. Cotton, cotton blends, and other cellulosic fabrics are treated with melamine-type prepolymers and N-methylol crosslinking agents that are applied from aqueous solutions which induce swelling of the cellulosic fibers and facilitate diffusion of the agents into these swollen fibers; the treatment yields a polymerization or fibersetting"which is achieved by subjecting the wet-impregnated textile to exposure to the boiling vapors of a relatively low boiling organic solvent, particularly a chlorinated hydrocarbon. Modifications have been incorporated into the process whereby specific effects are produced. Creasing of garments prior to a final curing step can be done to give creases and smoothness durable to repeated laundering.

The main object of the present invention is to provide a new process for polymer fixation within fibers of a cellulose-containing textile material in the vapors of a boiling organic solvent.

A second object of this invention is to provide a onestep durable press finishing treatment through polymer fixation and crosslinking of the cellulosic chains of the textile material that is carried out in the vapors of a boiling organic solvent and is particularly amenable to the treatment of flat goods.

A third object of the invention is to provide a twostep process for polymer fixation and crosslinking to yield durable press textile materials. In this variation of the invention either or both steps of the treatment are carried out in the hot vapors of a boiling organic solvent. Between the first step, in which the primary reaction occurring is polymer fixation with no, or a negligible amount of cellulose cross-linking, and the second step, in which the principal reaction is celulose crosslinking to set the imposed configuration into the textile material, a creasing operation can be included. This two-step variation of the invention with creasing between the steps gives a wrinkle resistant material with excellent creases and smooth drying properties that are durable to repeated laundering.

It is a further object of the present invention to achieve these goals and yet maintain high levels of the important mechanical properties such as strength, abrasion resistance, and the like in the treated fabrics.

The objects of the invention are obtained through a relatively low temperature solvent vapor finishing system. Durable press fabrics with an improved balance of performance properties result from the treatments. in the finishing system, which has been termed the Fiberset" process, cotton or cotton blend fabric is impregnated with an aqueous solution containing a cellulose reactive melamine pre-polymer and an N-methylol crosslinking agent. The cellulosic fibers of the textile material are swollen by the aqueous solution and the finishing components readily diffuse into the fibers. Water content of the impregnated fabric is adjusted by squeezing and, in some cases, partial drying. This is followd by |bersetting,"or polymer-fixation and cellulose crosslinking, in the vapors of a relatively low boiling organic solvent, characteristically a chlorinated hydrocarbon, which sets the preswollen cellulosic fibers in an open, relaxed state, prior to crosslinking.

DEFINITIONS For purposes of this specification the use of the word FIBERSET connotes the finishing system in which polymer fixation within the cellulosic fibers of the textile material being treated is carried out by exposure of the moisture-adjusted, impregnated textile material to the vapors of a boiling organic solvent. Fixation of the polymer within the fiber sets the fiber in the swollen state produced during impregnation of the fibers with an aqueous solution of the finishing agents. With proper selection of the solvent to provide the vapor medium for the solvent vapor curing step, polymer fixation occurs without collapse and complete dehydration of the fiber. The fibers are thus set in an open, relaxed state which contributes to better strength, wear, and appearance characteristics in the final textile products.

DURABLE PRESS is a term widely used in the textile, garment, retail, and associated industries. It is used interchangeably with permanent press to describe the ability of a garment to maintain its shape-retaining properties throughout its life. This means sharp creases, smooth fabric surface appearance, and seams free from puckering.

THE PRlOR ART Researchers have shown that polymer deposition without a swollen cotton fiber prior to crosslinking has given durable-press cottons with properties superior to those of cottons crosslinked by ordinary oven curing techiques.

The products of the prior art have been produced by processes identified as Wet Fixation," Polyset 1,", Polyset ll," and Steamset. Wet Fixation is explained by Hollies, in Vol. 37 1967 page 277, ofTextile Research Journal. Reeves, et al discuss Polyset l in Vol. 37 (1967), page 76, of the same journal. Hamaleinen et al., in Vol. 133, (March l969), page l3] of Textile Industries, present the philosophy of One-Step DP for Cottons." Verburg, et a]. define Steamset in Low Temperature Steam Setting of Resins," which appears in Textile Chemists and Colorists, Vol. 1, 1969, p. 595. In general, these processes of the prior art involve the introduction into the cotton fiber of a polymer-former usually a melamine derivative and a crosslinking agent such as dimethylol dihydroxyethyleneurea (DMDHEU). Under conditions of strong catalysis and relatively low temperature the two nitrogenous agents react to form a polymer within the fiber with little or no crosslinking of the cellulose chains. In a second step, crosslinking takes place and the crosslinked swollen fiber is less brittle, has better resistance to abrasion, and better strength properties than ovencured samples with equivalent wrinkle resistance. Often, the wet wrinkle-recovery angle is higher than the conditioned angle, and the moisture regain is higher. Both of these are indications that crosslinking has occurred while the fiber is in the swollen state.

SOLVENT FINISHING IN THE PRIOR ART An area of textile finishing that has received a great deal of attention in recent years is that of treatment in organic solvent media rather than in aqueous media. Efficient industrial processes have been developed for fabric preparation and the application of several types of surface treatments from solvents. However, progress in durable press finishing from solvent media has been slow.

There are several incentives which have encouraged the textile industry to pursue the objective of solvent finishing. Among these are the increasing scarcity and cost of high quality water, the demands for effluent control to prevent stream pollution, the potential of reduced processing costs, and the possibility of innovation to establish proprietary advantages. Because of cost, availability, toxicity, and flammability, serious consideration for solvents for finishing has been limited to three chlorinated hydrocarbons, perchloroethylene, trichloroethylene, and l,l,l-trichloroethane. The use of any solvent, or course, requires a highly cfficient recovery system; recovery of 95 percent is conssidered a bare minumum. Loss of solvent through partitioning effects with water drawn off during processing can be a problem. Decomposition of the chlorinated solvents to give HCl also is a problem that must be prevented. Furthermore, for serious consideration solvent processing must accomplish the finishing treatment as well or better than the corresponding aqueous treatment.

For durable press finishing of cellulosic fibers which depends upon a uniform crosslinking reaction throughout the fiber, solvent finishing is more difficult than conventional aqueous treatment methods. A major problem is that the solvents do not swell cotton sufficiently to permit penetration of finishing agents into the fiber when application is directly from a solvent solution. A brief steaming (perhaps seconds) prior to treatment has been suggested as an aid to penetration of the finishing agent.

There is immediate wetting of the fibers by the solvent, but without swelling of the fiber, penetration of the finishing agent is prevented and a surface treatment results rather than the needed homogeneous treatment. Furthermore, most N-methylol finishing agents are not sufficiently soluble in the organic solvents for use in solvent finishing. Two alternatives have been suggested to circumvent this problem: N-methoxymethyl deriva tives, methyl ethers of the N-methylol agents, which are soluble in the solvents have been used; and emulsification (water-in-oil emulsion) of the N-methylol agents have been used. The latter technique permits use of readily available agents and the 510 percent water present in the emulsion serves to provide some swelling of the fiber and aids in diffusion of the agent into the substrate.

When solvent finishing first appeared to be gaining in industrial acceptance, it was believed that new agents with functions different than the conventional methylol amide type would be quickly introduced. Although it would seem that whole new families of agents would be applicable in solvent finishing, no radical departures from the traditional N-methylol agents have yet assumed importance.

EVOLVEMENT OF THE PRESENT INVENTION Recently, a new method of treatment has been developed in which reaction between cellulose and crosslinking agents is promoted by curing in solvent vapor. A full description of the method has been presented by Cashen, Reinhardt, and Reid, the present inventors, at the A.A.T.C.C. Symposium on Textile Solvent Technology Update 73 which was held in Atlanta, Georgia on January -1], 1973, and is published on pages 79-90 of the Proceedings of this symposium. In this method of curing, cotton, suitably impregnated with finishing agent and catalyst, is crosslinked by heating in the vapors of a boiling solvent, such as a chlorinated hydrocarbon, preferably one such as trichloroethylene, perchloroethylene, or 1,] ,l-trichloroethane which form azeotropes with water that have boiling points below that of water. With suitable adjustment of treatment conditions, finished fabrics similar to those of conventional pad-dry-cure processing or of moist cure processing were obtained. Efficiency of vapor cure finishing was very high. Among variables that influenced properties of the finished fabrics were the nature of the solvent, finishing agent, and catalyst, and the amount of water in the fabric at the time of cure. With strong catalysts, very short curing times are needed. Even with moderately active catalysts, curing for a few minutes or less was effective. Similarly, moist cure effects were achieved in minutes instead of hours. Equivalent treatments by vapor cure, pad-dry-cure, and boiling liquid solvent finishing were compared. Strengths and efficiencies of the vapor cured fabrics were better than those of equivalent oven or solvent treatments.

In the above-mentioned presentation, Cashen et a], disclosed the fixation of a methylated methylolmelamine in cotton fabric by the vapors of boiling trichloroethylene which is an important factor in the present invention. [t was shown that even after as much as 30 minutes exposure to the vapors of boiling trichloroethylene, the fabric retained about 6-7 percent water content; fixation thus was in the swollen state of the fiber. This type of fixation was termed fibersetting and further investigation revealed a number of advantages of such processing over wet fixation processes of the prior art.

ADVANTAGES OVER PRIOR ART Among the advantages of the solvent vapor fixation process of the present invention are short fixation times due to the feasibility of using elevated temperatures without the advantage-defeating danger of fixation under drying conditions which cause fiber collapse and the associated well-known consequences (fiber embrittlement, drastic losses of strength and wear resistance, etc.) of conventional pad-dry-cure finishing. Further, since elevated fixation temperatures can be employed without over-dehydration of the fibers, less strong catalyst systems are operable which again contribute to more favorable properties in the fixed fibers. Fixation temperatures in solvent vapor fixation treatments are precisely deten'nined by the boiling point of the organic solvent employed and that of its water-azeotrope. These temperatures are physicochemical constants and are not subject to variation as in thermally controlled processing in hot air, superheated steam, and the like. No pressure equipment is needed for fibersetting in solvent vapors.

The constrast of these advantages and the disadvantages of wet fixation, Polyset l, Polyset ll, Steamset, and similar fixation processes of the prior art are obvious. Prior art processes suffer, in particular, from inconsistent results due to the necessity of precise control of processing conditions and from the need of expensive pressure and steam equipment. Processing conditions of fixation must be controlled so precisely that slight variations cause either under-fixation, and consequently inadequate polymer yield to give the needed finish, or over-fixation, and consequently finished fabrics, not with the desired properties produced by wet fixation, but with properties characteristic of finishing in a completely dehydrated state.

The present invention deals with a process wherein the cellulosic textile is impregnated with an aqueous solution of finishing agents and catalyst which induces swelling of the fibers and facilitates diffusion of the agents into the fibers; said treatment solution contains either a methylated methylolmelamine prepolymer adjusted to a pH of 2 or a mixture with a crosslinking agent; the water content of the impregnated fibers is adjusted to about 30-60 percent water; and exposing the textile to the vapors of certain boiling chlorinated solvents, and in so doing azeotropically lowering the water content of the impregnated fabric to about 5-7 percent, during which time a combination of fixation by polymerization and varying degrees of crosslinking can be achieved. The process is amenable to treatment of flat goods and for use with a creasing step after polymer fixation followed by a curing step to give durably creased, smooth drying, durable press textile products. The following examples are provided to illustrate the varying facets of the present invention. They are not meant as limitations of the invention in any manner whatever.

EXAMPLE 1 Wrinkle and abrasion resistant cellulosic fabric was produced in a process whereby 80 X 80 cotton printcloth was padded at 50 p.s.i. in a solution of the following composition: 5 percent solids of methylated methylolmelamine (Aerotex 238), 0.2 percent alkyl aryl ethyleneoxide alcohol (Triton-X-lOO) in water. The solution was adjusted to pH 2 with hydrochloric acid. After padding the fabric was dried at 60C to the equivalent of 30 percent retained water, then was exposed to the vapors of trichloroethylene at the boil (87C) for ten minutes. The fabric was then washed and dried in a hometype washing machine and tumble dryer (gas). Conditions of treatment and fabric properties are shown in Table 1 as Treatment A.

EXAMPLE 2 The treatment and materials of Example 1 were repeated, except percent solids of a melamine type prepolymer, methylated methylolmelamine (Aerotex 238) was used. Results are given as Treatment B of Table l.

EXAMPLE 3 The treatment and materials of Example 1 were repeated, except 14 percent solids of a melamine type prepolymer, methylated methylolmelamine (Aerotex 238) was used. Results are given as Treatment C of Table 1.

EXAMPLE 4 The treatment and materials of Example 3 were repeated, except the pad bath also contained 14 percent solids of a crosslinking resin, dimethyloldihydroxyethyleneurea (Permafresh I83), and after drying as described, the fabric was exposed to the vapors of boiling trichloroethylene 87C) for minutes. Results are given as Treatment D of Table 1.

EXAMPLE 5 The treatment and materials of Example 4 were re peated. except the padded fabric was dried to 60 percent residual water prior to solvent vapor fixation and cure. Results are given as Treatment E of Table 1.

EXAMPLE 6 The treatment and materials of Example 5 were repeated, except that the padding solution contained also 0.6 percent zinc nitrate hexahydrate as catalyst and, after fixation, the airdried fabric was creased in a hothead press at approximately C for 30 seconds and then cured in a forced draft oven at 160C for 3 minutes. Results are shown as Treatment F of Table [1.

EXAMPLE 7 The treatment and materials of Example 4 were repeated, except this was followed by re-padding the fabric in an aqueous solution containing 0.6 percent zinc nitrate hexahydrate, then rapid air-drying and creasing in a hot-head press at approximately 90C for 30 seconds, and post-curing in a forced draft oven at 160C for 3 minutes. Results are shown as Treatment G of Table II.

EXAMPLE 8 The treatment and materials of Example 7 were repeated, except that the post-cure catalyst was 2 percent aluminum chloride hexahydrate and post-curing was carried out in the vapors of perchloroethylene at the boil (121C) for one minute. Results are shown as Treatment H of Table ll.

EXAMPLE 9 Wrinkle and abrasion resistant cellulosic fabric was produced in a process whereby 8 ounce cotton twill was padded at 40 p.s.i. in a solution of the following composition: 14 percent solids of methylated methylolmelamine (Aerotex 23S), 14 percent solids of a crosslinking resin, dimethyloldihydroxyethyleneurea (Permafresh 183), 0.2 percent alkyl aryl ethyleneoxide alcohol (Triton X-) in water. The solution was ad justed to pH 2 with hydrochloric acid. After padding the fabric was dried in a forced draft oven at 60C to the equivalent of 60 percent retained water, then was exposed to the vapors of boiling trichloroethylene (87C) for five minutes. The fabric was washed and dried, then repadded to about 90 percent pickup with an aqueous solution containing 0.6 percent zinc nitrate hexahydrate, 3 percent of a fiber conditioner, in this instance a polyurethane (Polyurethane E-502 and 0.2 percent alkyl aryl ethyleneoxide alcohol (Triton X- 100). This solution, 400 grams, had a pH of 6.0, which was adjusted to pH 5.0 with two drops of diluted hydrochloric acid. This Fiberset fabric was then dried at 60C in a forced draft oven for ten minutes, and then either held as is for later curing, or immediately cured as follows: creasing of the fabric on a hot-head press at approximately 90C for 30 seconds, and post curing in a forced draft oven at C for five minutes. Results are shown as Treatment 1 of Table 11.

EXAMPLE 10 The treatment and materials of Example 9 were repeated, except polymer fixation was carried out in vapors of boiling trichloroethylene (87C) for 15 minutes. Results are shown as Treatment J of Table I1.

EXAMPLE 1 l The treatment and materials of Example 9 were repeated, except after padding, the fabric was dried in a forced draft oven at 60C to the equivalent of 30 percent retained water. Results are shown as Treatment K of Table II.

EXAMPLE l2 EXAMPLE 14 The treatment and materials of Example 1 l were re- The treatment and materials of Example 13 were repeated, except that after padding and drying, the fabric peated, except the fabric was 5.3 ounce per square yard was exposed to the vapors of boiling trichloroethylene 20/80 Polyester-Cotton sheeting of special 109w X 58f (87C) for IS minutes. Results are shown as Treatment construction. Results are shown under Fabric as 20/80 L of Table II. Polyester-Cotton of Table ll].

EXAMPLE l3 EXAMPLE The treatment and materials of Example 9 were re- The treatment and materials of Example 13 were repeated, except the fabric was 5.3 ounce per square yard peated, except the fabric was 5.3 ounce per square yard cotton sheeting of special 109w X 58f construction, and 30/70 Polyester-Cotton sheeting of special 109w 58f that the Fiberset fabric was dried at 60C in a forced construction. Results are shown under Fabric as 30/70 draft oven for seven minutes, and the postcure was for Polyester-Cotton of Table Ill.

TABLE I A STUDY OF FIBERSET" PARALAEI'ERS Polymer Fixation Post/cure Fabric Properties Brk. Str. Abrasion Wrinkle Predry Fixation of Resistance Recovery Pad Bath to Time Pad Add- Untr. (Stoll Flex) Angle Crease Sample Agent Catalyst ,0 min. Bath Method on of Untr. Cond. Wet Rating One-Step Process A 5% MM pH 2 30 I0 62 244 l B l0% MM pH 2 10 7O 245 260 c 14% MM pH 2 3o 10 12 71 265 271 D 14% MM+ pH 2 30 15 21 28S 29] 14% DMDHEU E l4% MNH- pH 2 I5 23 271 292 I4% DMDHEU Note: Refer to footnotes of Table II.

TABLE I] A STUDY OF FIBERSEI" PARAMETERS Polymer Fixation Postcure Fabric Properties Pre Fixa- Brk Abrasion Wrinkle dry tion Str. Resistance Recovery Crease Sam- Pad Bath to Time Addof (Stoll Flex) Angle Ratple Agent Catalyst H O min. Pad Bath Method on Untr. %of Untr. Cond. Wet ing' Two-Step Process F l4% MM+ 0.6% 60 I5 None St. Pres 5.2 82 26 236 266 5 l4% DMDHEU Zn(NO ),.6H,O Oven l60 G l4% MNH- pH 2 30 15 0.6% St. Press 59 I4 288 295 5 l4% DMDHEU Zn(NO,),.6H,O Oven H 14% MM+ pH 2 30 15 2% Vapor l2l 47 294 295 14% DMDHEU AlCl,.6H,O 5 l 14% MM+ pH 2 60 5 0.6%

14% DMDl-[EU Z.n(N0=),.6H,0 St. Press 9 B5 47 285 287 5 +31% polyurethane Oven 160 J [4% MM+ pH 2 60 I5 0.6% St. Pres 78 26 292 287 4.3

l4% DMDHEU Zn(NO;) .6H O Oven 160 +3% polyurethane K l4% MM+ pH 2 30 5 0.6% St PreS 78 37 296 283 5 14% DMDHEU Zn(NO;,) .6H- O Oven 160" +3% polyurethane L 14% MM+ pH 2 30 15 0.6% St. Press 77 3l 305 299 4.5

14% DMDHEU Zn( NO ),.6H,O Oven 160 +3% polyurethane MM rnethylolatcd melamine, DMDHEU dimethylol dihydroxyethylencurea Pad hath adjusted to pH 2 with hydrochloric acid Percent water based upon original weight of the fabric Fixation in the vapor! of boiling trichlorocthylene (WIT) Curing in the va ors of boiling perchloroethylene l2lC) Scale of l to S ranging poor to excellent respectively Table III A LISTING OF PHYSICAL PROPERTIES OBTAINED WITH FIBERSET' CHEMlCALLY FINISHED COTTON AND COTTON-BLEND SHEETING 5 min, Fixation in trichloroethylene vapors (87C) Percent untreated control We claim:

1. A process for imparting durable-press properties to cellulosic textiles, the process comprising a. impregnating the textile with an aqueous solution containing a methylated methylolmelamine prepolmer, thereby swelling the textile;

b. adjusting the water content of said impregnated textile to about from 30 to 60 percent;

c. and exposing the textile to step (b) to the vapors of a chlorinated hydrocarbon capable of forming an azetrope with water which has a boiling point below that of water, for a sufficient time to azeotropically lower the water content of the step (b) textile to about 5-7 percent.

2. The process of claim 1 wherein the aqueous solution of step (a) also contains dimethyloldihydroxyethyleneurea crosslinking resin and the textile of step (c) is further impregnated with a catalyst for said resin, pressed to the desired configuration and cured in an oven for about 3 to 5 minutes at about 160C.

3. A process for imparting durable press properties with improved strength to cellulosic textiles, the pro cess comprising:

a. impregnating a cellulosic textile with an aqueous solution containing about 5-14 percent ofa methylated methylolmelamine prepolymer, adjusted to a P b. partially drying in an oven at 60C to about from 30 to 60 percent water content, and

c. exposing the textile of (b) to the vapors of boiling trichloroethylene for about from 5 to minutes, during which time water is removed azeotropically to about from 5 to 7 percent content and during which time fixation by polymerization occurs.

4. A process for imparting durable press properties with improved strength to cellulosic textiles, the process comprising:

a. impregnating a cellulosic textile with an aqueous solution containing about 14 percent ofa methylated methylolmelamine prepolymer and 14 percent of dimethyloldihydroxyethyleneurea, the solution adjusted to a pH of 2,

b. partially drying the impregnated textile at 60C to obtain a water content of about from 30 to 60 percent. and

c. exposing the textile of (b) to the vapors of boiling trichloroethylene for about from 5 to 15 minutes, during which time water is removed azeotropically to about from 5 to 7 percent content and fixation by polymerization occurs.

5. A process for imparting durable press properties with improved strength to cellulosic textiles, the process comprising:

a. impregnating a cellulosic textile with an aqueous solution containing about 14 percent of a methylated methylolmelamine prepolymer, about 14 percent of.dimethyloldihydroxyethyleneurea, and 0.6 percent zinc nitrate hexahydrate catalyst,

b. partially drying the impregnated textile at 60C to obtain a water content of about 60 percent,

c. exposing the textile of (b) to the vapors of boiling trichloroethylene for about 15 minutes to remove water azeotropically to a water content of about from 5 to 7 percent,

(1. storing the material until needed for fabrication of garments or other articles,

e. steam pressing after fabrication at about C to impart the desired configuration and creases, and

f. oven curing the shaped and creased material for about 3 to 5 minutes at about C.

6. A process for imparting durable press properties with improved strength to cellulosic textiles, the process comprising:

a. impregnating a cellulosic textile with an aqueous solution containing about 14 percent of a methylated methylolmelamine prepolymer, and about 14 percent of dimethyloldihydroxyethyleneurea, the solution adjusted to a pH of 2,

b. partially drying the impregnated textile at 60C to obtain a water content of about 60 percent,

c. exposing the textile of (b) to the vapors of boiling trichloroethylene for about 5 to 15 minutes, to remove water azeotropically to a water content of about from 5 to 7 percent,

d. washing and drying the textile of (c),

e. impregnating the dry textile with an aqueous solution containing 0.6 percent zinc nitrate hexahydrate, and 0 percent to 3.0 percent polyurethane softener, to a wet pickup of about 90 percent, and

f. curing the textile for about 3 to 5 minutes at about 

1. A process for imparting durable-press properties to cellulosic textiles, the process comprising a. impregnating the textile with an aqueous solution containing a methylated methylolmelamine prepolmer, thereby swelling the textile; b. adjusting the water content of said impregnated textile to about from 30 to 60 percent; c. and exposing the textile to step (b) to the vapors of a chlorinated hydrocarbon capable of forming an azetrope with water which has a boiling point below that of water, for a sufficient time to azeotropically lower the water content of the step (b) textile to about 5-7 percent.
 2. The process of claim 1 wherein the aqueous solution of step (a) also contains dimethyloldihydroxyethyleneurea crosslinking resin and the textile of step (c) is further impregnated with a catalyst for said resin, pressed to the desired configuration and cured in an oven for about 3 to 5 minutes at about 160*C.
 3. A process for imparting durable press properties with improved strength to cellulosic textiles, the process comprising: a. impregnating a cellulosic textile with an aqueous solution containing about 5- 14 percent of a methylated methylolmelamine prepolymer, adjusted to a pH 2, b. partially drying in an oven at 60*C to about from 30 to 60 percent water content, and c. exposing the textile of (b) to the vapors of boiling trichloroethylene for about from 5 to 15 minutes, during which time water is removed azeotropically to about from 5 to 7 percent content and during which time fixation by polymerization occurs.
 4. A process for imparting durable press properties with improved strength to cellulosic textiles, the process comprising: a. impregnating a cellulosic textile with an aqueous solution containing about 14 percent of a methylated methylolmelamine prepolymer and 14 percent of dimethyloldihydroxyethyleneurea, the solution adjusted to a pH of 2, b. partially drying the impregnated textile at 60*C to obtain a water content of about from 30 to 60 percent, and c. exposing the textile of (b) to the vapors of boiling trichloroethylene for about from 5 to 15 minutes, during which time water is removed azeotropically to about from 5 to 7 percent content and fixation by polymerization occurs.
 5. A process for imparting durable press properties with improved strength to cellulosic textiles, the process comprising: a. impregnating a cellulosic textile with an aqueous solution containing about 14 percent of a methylated methylolmelamine prepolymer, about 14 percent of dimethyloldihydroxyethyleneurea, and 0.6 percent zinc nitrate hexahydrate catalyst, b. partially drying the impregnated textile at 60*C to obtain a water content of about 60 percent, c. exposing the textile of (b) to the vapors of boiling trichloroethylene for about 15 minutes to remove water azeotropically to a water content of about from 5 to 7 percent, d. storing the material until needed for fabrication of garments or other articles, e. steam pressing after fabrication at about 90*C to impart the desired configuration and creases, and f. oven curing the shaped and creased material for about 3 to 5 minutes at about 160*C.
 6. A PROCESS FOR IMPARTING DURAVLE PRESS PROPERTIES WITH IMPROVED STRENGTH TO CELLULOSIC TEXTILES, THE PROCESS COMPRISING: A. IMPREGNATING A CELLULOSIC TEXTILE WITH AQUOUS SOLUTION CONTAINING ABOUT 14 PERCENT OF A METHYLATED METHYLOLMELAMINE PREPOLYMER, AND ABOUT 14 PERCENT OF DIMETHYLOLDIHYDROXYETHYLENEUREA, THE SOLUTION ADJUSTING THE A PH OF 2, B. PARTIALLY DRYING THE IMPREGNATED TEXTILE AT 60*C TO OBTAIN A WATER CONTENT OF ABOUT 60 PERCENT, C. EXPOSING THE TEXTILE OF (B) TO THE VAPORS OF BOILING TRICHLOROETHYLENE FOR ABOUT 5 TO 15 MINUTES, TO REMOVE WATER AZEOTROPICALLY TO A WATER CONTENT OF ABOUT FROM 5 TO 7 PERCENT, D. WASHING AND DRYING THE TEXTILE OF (C), E. IMPREGNATING THE DRY TEXTILE WITH AN AQUEOUS SOLUTION CONTAINNING 0.6 PERCENT ZINC NITRATE HEXAHYDRATE, AND 0 PERCENT TO 3.0 PERCENT POLYURETHANE SOFTENE, TO A WET PICKUP OF ABOUT 90 PERCENT, AND F. CURING THE TEXTILE FOR ABOUT 3 TO 5 MINUTES AT ABOUT 160*C. 